1. Field of the Invention
The invention relates to a process for damping vibrations during the winding of material webs, in particular paper and cardboard webs, in which the process includes at least two bodies, e.g., a winding reel and an adjacent roll, arranged to form a nip, and that, through imbalance or out-of-roundness, the two bodies together form a system capable of vibration.
The invention also relates to a winding machine structured to perform a winding process that includes the at least two bodies arranged to form a nip, such that imbalance or out-of-roundness of at least one of the two bodies creates vibrations in the machine.
2. Discussion of Background Information
Winding machines are known in many different designs and are used to wind a material web to form wound reels. In the production of paper or cardboard webs, winding of finished web several meters wide takes place either at the end of the paper machine or at the end of a downstream coating machine. Such winding machines are known, e.g., from German Patent Application No. DE 40 07 329 A1 and European Patent Application No. EP 0 792 829 A2. The winding machine from German Patent Application No. DE 40 07 329 A1 is equivalent to the construction type of the so-called Pope reel. European Patent Application No. EP 0 792 829 A2 shows a different construction type of a Pope reel in which the winding axis remains stationary during winding, but the press roll is displaced horizontally as the reel grows larger.
In order to produce narrower winding reels with a higher winding quality, the web is divided by several longitudinal slits into individual webs which are wound onto cores usually made of paperboard.
This winding on cores takes place either on so-called support roller type winding machines or on so-called backup roll winding machines. A support roller winding machine in which the webs are wound in an upper gusset (spandrel) between the two support rolls is known from document International Application No. WO 93/25461. Guide heads engage in the outer ends of the outer cores to prevent an axial displacement of the winding reels in the winding bed. International Application No. WO 93/15988 discloses a winding machine that features only one roll, and this winding machine is also referred to as a backup roll winding machine. In the upper area of this backup roll, the winding reels rest offset to one another in an alternating manner with respect to the apex line (crown) of the backup roll. Guide heads engage in the cores of the winding reel on both sides to hold the winding reels on the backup roll, which guide heads are connected to piston cylinder units to reduce the bearing load of the winding reels on the backup roll.
Another prior art, German Patent Application No. DE 32 43 994 A1, describes a support roller type winding machine in which a total of three support rolls are available next to each other in an axially parallel way. This results in a total of two winding beds in which the winding reels are arranged in an alternating manner.
These cited winding machines have in common that at least one roll and at least one winding reel together always form a pressure line. In part, these winding machines also have an additional press roll which provides the winding reels with an additional contact pressure, e.g., from above. Likewise, the cited winding machines have in common that vibrations can occur, e.g., through imbalance of the rolls and above all through the winding reels. The vibrations caused by imbalance are synchronous with the rotational frequencies of the rolls or the winding reels. However, fluctuations, e.g., in the thickness of the material to be wound, lead to circumferential out-of-roundnesses of the surface in the case of the winding reels. This triggers additional vibrations which with support roller type winding machines can lead in extreme cases to the winding reel jumping out of the winding bed.
German Patent Application No. DE 196 29 205 A1 describes a process and a device for winding up a paper web into a wound reel with vibration damping. Here a Pope reel is developed into a system vibrating in phase opposition with the aid of coordinated elastic mass systems, in connection with dampers (shock absorbers) in parallel connection and/or series connection. This system is realized either still with an additional mass able to vibrate or with an infinite additional mass, e.g., in the form of a wall. Although the determination of the horizontal vibration portions is made by movement sensors to coordinate the system, through this coordination, the system can only vibrate in a typical fundamental frequency (which essentially corresponds to the rotational frequency of the winding reel) and in integral multiples of the fundamental frequency. A direct reaction to momentary, a periodic unevennesses of the winding reel, thus to frequency fractions smaller than the rotational frequency, is not possible.